Modelling and prognosis
Forest inventory outcomes and data are utilised in several ways. Several factors contribute to this multifarious use. On the one hand, the methodology of forest resource assessment is developed in a manner to meet user expectations which are defined much in advance, and on the other hand this methodology relies on existing knowledge, i.e. it uses information from forestry and peer sectors and aligns itself to approved national and international nomenclatures and definition systems.
These sound foundations the serial application which emanates from the character forest inventories render forest inventory data usable in a variety of models and prognoses.
Forest science and literature give priority to discussing the issue of and the opportunities for modelling and prognoses.
"Forestry prognoses are much more reliable because of the length of the production period, the relatively slow change of forest related social needs and the capacity of forests to regulate themselves. That is why it is quite easy, and also relatively uninteresting, to insert a prognosis of the forestry sector into an agricultural program spanning one or two decades.
It is more interesting for us to work with larger forest stands and greater time horizons and to develop routes across time that converge towards a favourable target status. Long term regulation of generation is a tradition in forestry. Initially objectives called for reaching a set (simplified and artificial) target status directly and rapidly (blocking for felling, cutting cycles), while the strategies that were developed later on were based on mitigating departures from the vision and approximating the target status gradually and asymptomatically were developed (such as the Hundeshagen formula, the formula of the Austrian Chamber, the 1880 formula of the Ministry of Agriculture and the ESBA procedure)."
- Király László - dr. Mészáros Károly: Konvergens prognózisok szerepe az erdőgazdasági stratégiák tervezésében, Erdészeti és Faipari Tudományos Közlemények 1994-1995, p137
"The analysis of forest stocks containing several tree stands is the competence of forest management planning and supervision. This includes static analysis such as forest inventories, and dynamic analysis, which covers forest stock modelling. Forest crop model: a table, nomogram, function or algorithm that shows how the major parameters of forest stocks with tree stands of a particular tree species or a composition of tree species change in time."
Dr. Veperdi Gábor: Erdőbecsléstan, Sopron, 2009.
"In the forest management sector, it is important to foresee the dynamism of tree stands, and to ensure opportunities for supervising their development. The advancement of computer technology revolutionized the dynamic modelling of tree stand development as of the early 1980s.
In terms of methodology, three fundamental model types are distinguished:
- growth models: to model the growth of a factor of tree stand structure over a specific period;
- yield models: to model the product of a tree stand (e.g. volume) for a specific point in time.
- a combination of the two models are growth models that also present forest crop data for various specific stages of growth."
Dr. Veperdi Gábor: Faterméstan, Sopron, 2008.
The method of convergent prognoses by Dr. László Király
This procedure supports the creation of prognoses that converge to (one or more) visions based on forest inventory and management planning data and a study of changes in past periods. These prognoses are based on forest crop models at compartment level and on regular forest models at forest stock level.
The method developed by Dr. László Király has also been applied in practice and has helped discussions between special authorities, civil society organisations and forest managers on several occasions.
For further information see: dr. Király László - dr. Mészáros Károly: Konvergens prognózisok szerepe az erdőgazdasági stratégiák tervezésében, Erdészeti és Faipari Tudományos Közlemények 1994-1995, p137
The method of yield regulation by Dr. István Bán
Dr. Bán used a variety of methods during his active years, including Final Harvest Optimisation (FHOPT) and Using maximum straightening to define the budgeted figures of final harvest yield regulation. He developed the National Final Harvest Yield Regulation for the period between 1992 and 2031.
For further information see: Dr. Bán István: Erdészeti alkalmazott biomatematika, Budapest, 1996
EFISCEN
The European Forest Information SCENario (EFISCEN) is a large-scale forest model that projects forest resource development on regional to European scale. The model is suitable for the projection of forest resource development for a period of 50 to 60 years
The model uses national forest inventory data as a main source of input to describe current forest resources. Based on this information, the model can project the development of forest resources, based on different scenarios. These scenarios are mainly determined by management actions, but the model can also take into account changes in forest area, as well as changes in growth e.g. due to climate change.
EFISCEN has been jointly developed and applied by Alterra and EFI. For further information see: http://www.efi.int/portal/virtual_library/databases/efiscen/